Cnet: Based on his own research, Ancestry.com founder Paul Allen reports that Google+ now has more than 62 million users, and it has been adding 625,000 new users per day in December. Allen predicts that Google+ will hit 100 million users on February 25, 200 million on August 3, and 293 million by the end of next year.

"I expect the growth to continue to accelerate," Allen said. "Google can continue to integrate Google+ into its other products and word of mouth will continue to build. Most importantly, 700,000 Android devices are activated daily and this will become a very significant source of new users for Google+. That number will also grow next year."

However, Allen's statistics do not account for Google+ users who open an account but don't regularly return to the site.